Main Content

4-Speed CR-CR

Clutch schedule for a four-speed carrier ring-carrier ring transmission

  • 4-Speed CR-CR block

Simscape / Driveline / Transmissions


The 4-Speed CR-CR block consists of two planetary gear sets and five disk friction clutches. The follower shaft connects to the planet gear carrier of the output planetary gear and the ring gear of the input planetary gear. The clutches are configured to implement four ratios, one reverse ratio, and neutral. The reverse clutch and two of the clutches determine which gears the base shaft connects to. The other two clutches act as brakes, grounding various gears of the planetary sets to the transmission housing.

This diagram shows a four-speed carrier ring-carrier ring transmission. The labels for the gear components are superimposed on the input and output gears. The table lists the gear and clutch components that are labeled in the diagram.

I.P.G.Input planetary gear
O.P.G.Output planetary gear
R Ring gear
CPlanet gear carrier
SSun gear
RReverse clutch
A–BForward clutches that control the power flow path
C–DForward, braking clutches

Drive Ratios, Clutch Schedule, and Power Flow

The drive ratio between the transmission input and output shafts follows from the elementary gear ratios specified for the gear blocks. The elementary gear ratios are





  • NRI is the number of teeth in the planetary ring gear on the input shaft side.

  • NSI is the number of teeth in the planetary sun gear on the input shaft side.

  • NRO is the number of teeth in the planetary ring gear on the output shaft side.

  • NSO is the number of teeth in the planetary sun gear on the output shaft side.

The table shows the clutch schedule, drive-ratio expressions, drive-ratio default values, and the power-flow diagrams for each gear of the 4-Speed CR-CR block.

The letters in the clutch schedule columns denote the brakes and clutches. A value of 1 denotes a locked state and a value of 0 an unlocked state. The clutch schedule generates these signals based on the Gear port input signal. The signals are scaled through a Gain block and used as actuation inputs in the clutch blocks.

The power-flow diagrams show the power flow paths between input and output shafts for each gear setting. Power flow is shown in orange. Connections to the transmission housing (a mechanical ground) are shown in black.

GearClutch ScheduleDrive Ratio EquationDefault RatioPower Flow







expand all

Specify -1 for reverse, 0 for neutral, and 1–4 for the forward gears.

Data Types: single | double


expand all

Conserving port associated with the base shaft.

Conserving port associated with the follower shaft.


expand all

Sets the initial engagement or disengagement of the clutches using the clutch schedule. When the transmission is in neutral, there is no power flow from the base shaft to the follower shaft.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2015a